CGTalk - IK hand and arm

Ryokukitsune

06-01-2005, 04:07 AM

I have an entire character rig set up minus the wrists due to one massive problem I’m having. I’m trying to have a controlling locator/object set at the wrist that controls set driven key anims as well as the wrist and ulna (forarm) rotations unfortunately for me I can’t get the rotations to work correctly.

I have tried using the connection editor to directly attach the rotations to the locator but only the X rotate works. I’ve also tried orienting the joints to the locator but unfortunately the rotations get really weird.

Can anyone direct me to a tutorial on how to set up a wrist controller? I need to figure this out asap because I'm working on a class project... please help!

thehive

06-02-2005, 07:18 PM

you can try pos & orient comstriant on a circle to the wirst then break that then orient the wirst to the circle then make the circle the partent of the IK hope that helps

brentorama

06-04-2005, 07:36 AM

Sorry, are you asking how to build a twisting IK rig?

fabianopetroni

06-29-2005, 10:34 AM

I use a little expression on my rigs to do the job , I select the forearm joint and do the following expression :

forearm.rotateX = WristControl.rotateX*.5

wich means that the forearm joint will rotate 50% related to the control (Wrist Control in that case wich is parent contrain to the ik), hope that help

brentorama

06-29-2005, 06:39 PM

That works for FK arms. How do you get it to work for IK arms pray?

aryzner

06-29-2005, 09:36 PM

I haven't rigged an arm in a while but does this work...?

-Orient constrain the wrist joint to your wrist controller, whatever it may be (I'm guessing a curve or something)

-Point constrain the IK handle to the wrist controller

-In connection editor, connect the rotate X of the wrist controller to the rotate X of the forearm joint

In order to get that 50% rotation of the forearm joint, I usually like to go into the hypergraph and do it with a multiply/divide node... but you could probably do it with that expression or some other way.

aryzner

06-29-2005, 09:44 PM

whoops this thread is like almost a month old.. I'm sure he's gotten his answer by now somehow

fabianopetroni

06-30-2005, 09:00 AM

this expression works for IK as well I use on my rigs., sorry i am kind new at foruns and did not know that is a month old sorry

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